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In this paper, we study a multiuser indoor Terahertz (THz) communication system with antenna array. To capture the distance-frequency dependent peculiarities of THz channels, we design a distance-aware multi-carrier transmission scheme with hybrid beamforming and antenna subarray selection. Specifically, a low complexity greedy subarray selection algorithm is proposed. Simulation results are provided...
This paper addresses the problem that how to estimate the channel practically for the large-scale multiple antenna systems. Based on the uniform linear array, we reformulate the signal model for channel estimation into a transform-domain (TD) representation. Then the TD filtering schemes are investigated. In particular, we propose a sequence-based filtering scheme, which is asymptotically optimal...
Solid-state drives (SSDs) have been widely deployed in large-scale storage systems. To guarantee high reliability for SSD-based storage systems, it still requires data redundancy schemes, e.g., RAID schemes. Traditional RAID-5 shows its benefits in load-balancing and I/O parallelism, and so it is still the first choice for enhancing the reliability of SSD RAID arrays. However, some SSDs under the...
There exist numerous erasure codes for RAID-6, of which MDS codes are popular due to the optimal storage efficiency. Although vertical MDS codes have better load balancing compared to horizontal MDS codes, unbalancing problem still exists in some vertical codes, e.g., P-Code. To address this issue, we propose a novel efficient RAID-6 code to support highly balanced I/Os among disk arrays - Balanced...
This paper presents a new method to estimate the direction of arrival (DOA), which is based on the reduced rank covariance matrix. The new method can reduce the computation complexity greatly and keep a good performance at the same time. For comparison purpose, we compare this new method with the classical multiple signal classification (MUSIC). The results of the root mean square error and the computation...
Mathematical morphology, initially devoted to binary and grey-level image processing, also offers opportunities to develop efficient tools for multivalued - and in particular, colour - images. In this context, connected operators are increasingly considered as a relevant way to obtain such tools, mainly for image filtering and segmentation purposes. In this article, we focus on connected operators...
The use of hash tables in high speed packet processing applications is widely adopted and many different variants of such structures have been proposed in the literature. Nonetheless, the extremely variegated scenarios of application call for new specialized solutions, to best satisfy their possibly peculiar requirements. In this paper, we propose a randomized approach to the design of compact hash...
Optimized version of the parallel breadth-first search algorithm is considered in the paper. An optimization method described in the paper allows reducing the overhead of the suggested algorithm on each its iteration. It is shown that the optimized parallel algorithm for GPU is more than five times faster than its sequential analog on CPU.
In this paper, a method for the design of a wideband beamformer with temporal sparsity is proposed. The main advantage of the proposed design is its low implementation complexity as the number of non-zero valued coefficients is reduced significantly. It is formulated as an l1 minimisation problem with an added frequency invariant (FI) constraint if an FI response is desired. As a result, sparsity...
Based on the high gain beam forming and overall spatial beam scanning properties of Luneburg lens, a phased monopole array mounted on the surface of a Luneburg lens is proposed. With controlled distributions of excitation amplitude and phase on four adjacent monopole elements, this monopole array can form continuously scanned beams instead of the conventional discrete beams. To demonstrate this feature,...
The growing complexity of computer system hardware and software makes their behavior analysis a challenging task. In this context, tracing appears to be a promising solution as it provides relevant information about the system execution. However, trace analysis techniques and tools lack in providing the analyst the way to perform an efficient analysis flow because of several issues. First, traces...
The recently developed Threaded Many-core Memory (TMM) model provides a framework for analyzing algorithms for highly-threaded many-core machines such as GPUs. In particular, it tries to capture the fact that these machines hide memory latencies via the use of a large number of threads and large memory bandwidth. The TMM model analysis contains two components: computational complexity and memory complexity...
This paper presents a new methodology based on the reduced rank covariance matrix for direction of arrival (DOA) estimation, which can be have lower complexity compare to the classical Multiple Signal classification (MUSIC). Since the reduced rank covariance matrix contains all the information that the traditional covariance has, the performance of the proposed method is almost the same with the classical...
This paper proposes a power/area efficient method for realizing a class of downsampled floating tap decision feedback equalization (DFE) architectures for serial links. The architectures offer significant complexity and power reduction over a standard floating tap DFE architecture with minimal performance loss. A shift register multi-phase clock based design in 28nm CMOS is implemented for operation...
We propose a performance-complexity tradeoff for vector perturbation (VP) precoding in the downlink of multiuser multiple input multiple output (MU-MIMO) systems, that bridges the gap between linear and non-linear channel-inversion type precoding. To this end, we introduce a VP design that applies a performance-determined threshold to the desired norm of the preceded signal, to reduce the search through...
The quest for ever faster pick-and-place robots has led to ingenious parallel robots with reduced mobility, e.g., capable of producing motions proper of SCARA systems: three independent translations and one rotation about an axis of fixed direction. These robots are also known as Schönflies-motion generators (SMG). Some parallel versions are commercially available, as are serial-parallel designs....
Linear nearest-neighbor search in high-dimensional data exposes high computational complexity. In order to minimize search complexity we employ optimal δN-nets of rank N, which consist of a sub set of N vectors out of an initial code book E, yet approximate all En vectors of E by the least error (denoted by the number theoretical concept of dispersion) of all possible selections of N vectors. In this...
This paper describes the results of a research project which is aimed at designing and realizing innovative multifunctional radar architecture based on Tile elements. In this paper we focus on the description of the design strategy of the antenna front end and on the digital beamforming architecture able to meet the performance requirements. In particular a suitable digital beamforming technique exploiting...
We present a new linear time algorithm for computing the Lempel-Ziv Factorization (LZ77) of a given string of length N on an alphabet of size σ, that utilizes only Nlog N + O(σ log N) bits of working space. When the alphabet size is small, this greatly improves the previous best space requirement for linear time LZ77 factorization (Kärkkäinen et al. CPM 2013), which is...
In the 35 years since its discovery, the Lempel-Ziv factorization (or LZ77 parsing) has become a fundamental method for data compression and string processing. In many applications, computation of the factorization is a time-space bottleneck. However, and despite the increasing need to apply LZ77 to massive data sets (for both storage and indexing), no algorithm to date scales to inputs that exceed...
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